This paper provides a comprehensive account of the distribution of miospore species which are considered to be stratigraphically significant in the Dinantian (Calciferous Sandstone Measures and Lower Limestone Group) of the Midland Valley of Scotland. Five miospore concurrent range zones are recognised in these beds:

Tripartites vetustus—Rotaspora fracta (VF) Zone

Raistrickia nigra—Triquitrites marginatus (NM) Zone

Perotrilites tessellatus—Schulzospora campyloptera (TC) Zone

Lycospora pusilla (Pu) Zone

Schopfites claviger—Auroraspora macra (CM) Zone

The distribution of these zones in the sections studied provides a method of correlation in a series of rocks, which are largely of non-marine origin and notable for their lack of stratigraphically useful macrofossils and for marked variations in facies and thickness. The zones have also been proved in sections of Lower Carboniferous rocks in the Northumbrian trough, thereby providing a potential method of correlation between the two areas.

Two new genera, Colatisporites and Biannulatisphaerites, are described and one Tricidarisporites emended. Fifteen new species and one new type are described, three species recombined and three emended. Representative assemblages of the miospore zones are illustrated.